Our proprietary "Fire-Lock™" Head gasket system has been proven in our record-setting race cars to be the strongest Subaru head gasket system ever produced. To achieve these results, our engineers separated the combustion chamber sealing from the fluid sealing aspects of the head gaskets. These gaskets have been tested in excess of 1000 horsepower.

This solution is loosely derived from diesel technology where a counterbore step is machined around each cylinder bore allowing specially sized fire rings to drop into the machined area and head gasket bores. The shims are designed to create a compression seal once the heads are installed and torqued into place. When producing the IAG 950 and 1150 closed deck cases, our machinists carefully machine a recess at the top of each cylinder to accept the "Fire-Lock™" ring. With the ring locked in place, it stands proud above the deck, providing a superior seal. IAG fire rings are manufactured to a very strict tolerance from a proprietary alloy and are then put through a heat treatment process. 14mm Head Studs are required for Fire-Lock™ Gaskets

The gaskets are manufactured from an asbestos-free composite raw material and feature silicone-based beading applied to critical areas to improve sealing around all water and oil passages. The separate gasket bodies take care of sealing oil and coolant passages, keeping them out of the combustion chamber. The combination of the alloy compression shims and gaskets assures maximum sealing for a Subaru EJ25 turbocharged engine. The IAG 950 & 1150 Cases are also machined to accept 14mm Head studs (Not Included) to ensure proper head gasket seal.

*The IAG Fire-Lock™ gaskets require machine work for installation.